Javier Borondo

Efficiency of human activity on information spreading on Twitter

Understanding the collective reaction to individual actions is key to effectively spread information in social media. In this work we define efficiency on Twitter, as the ratio between the emergent spreading process and the activity employed by the user. We characterize this property by means of a quantitative analysis of the structural and dynamical patterns emergent from human interactions, and show it to be universal across several Twitter conversations. We found that some influential users efficiently cause remarkable collective reactions by each message sent, while the majority of users must employ extremely larger efforts to reach similar effects. Next we propose a model that reproduces the retweet cascades occurring on Twitter to explain the emergent distribution of the user efficiency. The model shows that the dynamical patterns of the conversations are strongly conditioned by the topology of the underlying network. We conclude that the appearance of a small fraction of extremely efficient users results from the heterogeneity of the followers network and independently of the individual user behavior.

Measuring political polarization: Twitter shows the two sides of Venezuela

We say that a population is perfectly polarized when divided in two groups of the same size and opposite opinions. In this paper, we propose a methodology to study and measure the emergence of polarization from social interactions. We begin by proposing a model to estimate opinions in which a minority of influential individuals propagate their opinions through a social network. The result of the model is an opinion probability density function. Next, we propose an index to quantify the extent to which the resulting distribution is polarized. Finally, we apply the proposed methodology to a Twitter conversation about the late Venezuelan president, Hugo Chávez, finding a good agreement between our results and offline data. Hence, we show that our methodology can detect different degrees of polarization, depending on the structure of the network.

Adapting physics courses in an engineering school to the b-learning philosophy

In this paper we introduce the methodology that we have followed to convert traditional notes into interactive online materials. The idea behind this has been to make self-consistent and interactive online materials capable of motivating the students to get involved in the learning process. For this purpose, we have used the e-learning environment Moodle, which is a platform with a high interactivity potential. We conclude that the academic performance reaches its maximum when correctly combining self-organising with minimum teacher guidance.

Agricultural activity shapes the communication and migration patterns in Senegal

The communication and migration patterns of a country are shaped by its socioeconomic processes. The economy of Senegal is predominantly rural, as agriculture employs over 70% of the labor force. In this paper, we use mobile phone records to explore the impact of agricultural activity on the communication and mobility patterns of the inhabitants of Senegal. We find two peaks of phone calls activity emerging during the growing season. Moreover, during the harvest period, we detect an increase in the migration flows throughout the country. However, religious holidays also shape the mobility patterns of the Senegalese people. Hence, in the light of our results, agricultural activity and religious holidays are the primary drivers of mobility inside the country.

Agricultural activity shapes the mobility patterns in Senegal

The communication and migration patterns of a country are shaped by its socioeconomic processes. The economy of Senegal is predominantly rural, as agriculture employs over 70% of the labor force. In this work, we have used mobile phone records to explore the impact of agricultural activity on the mobility patterns of the inhabitants of Senegal. We have detected an increase in the migration flows throughout the country during the harvest season. At the same time, religious holidays also shape the mobility patterns of the Senegalese people, since, as in many cultures, they are related to climate seasons and agricultural activities. Hence, in the light of our results, agricultural activity and religious holidays are the primary drivers of mobility inside the country.

Characterizing and Modeling Collective Behavior in Complex Events on Twitter

All around the world people are increasingly using Internet and online social networks to relate among each other. This fact is bringing a unprecedented amount of user generated data, which is certainly attracting research on several fields. In this work we analyze the user interactions in Twitter around two politically motivated events, like a Venezuelan protest and the 2011 Spanish Presidential electoral campaign. We found that users participated quite heterogeneously, as a tiny fraction of them concentrates much of the activity or collective attention. This heterogeneity gives place to critical features, like interaction networks with power law distributions and modular structure. Although online social networks appear to be a pure social environment, we found traditional agents, such as well known politicians and media hold loads of influence among the participants.